kelley



' y 1945- c. s. KELLEY 2,376,489

SLACK ADJUSTER Filed June 25, 1942 2 Sheets-Sheet 2 m m% m m y 5 4 WJ 36(A u w 1 m mK. |Mfl 4 m h V IIII lol m 4 III e m 3 7 7 6 w O 2 2 B M m W7 m w w w m a m 6 a M w m 4 N l M 6 2 m a w 2 V 6 Gd ATTORNEY PatentedMay 22, 1945 STATE PATENT OFFICE 'llhisiilmention relates-Ito automatic.hrakeraip- 'p'azratus; anclz-morerparticnlarly to: slack adjustermeans.lcouperativevwith the-:brake-actuating elements on suchapparatusrtb compensateiorcwear.

:copendingipatent;applicatiom of. Arthur G? Lamom. PatentN;.2,'339;4:15., issued; January H, 1944, there issdisclosedi a;compact. braking mechanismitioir' vehicle: :drivez shait; comprising. arotaryhrakeo operating .elenmnt orrscamrshaft, ,-an

. 6- and 7- are-sectional. views .tBkena-lbng the T111188; 8 -5andtfls-krespectively, of Eig. 5. Embodimentsnbz mwmg. 1-

Refemving, to Fig. 1 of. the drawings... the- Slack adjuster apparatustherein. illustrated. is. designed. or association. with. the brakeequipment. .disclosed imthepatent applicationsupra. .It' will beunderstood. that pthis. brake equipment is 6911-.

srcuete leven'stcaddiin'gsthe vehicledrive: shaft 10 structedi and. nreflect. tarnplicflfim of endaopmbieaior actuating-1theioperatingxelement, a: brake: :ampiication:- spring cooperative. with:the lever wapplyibrakingttbrce;.andthydraulic presshire means alsocooperative with the: lever. 16 or .brakingvforce. toihewheelsnfthevehicle through the :medium sofi-atdrive..shaft. L0,. which is.operatively connected. .to the. wheelslby. means. 0fsuitableagearsandisalsnprovideiwith a brake. drum meeting the-measeortheorems. As isthecase and! internal expansionbmke-"shoe assembly with all 'typessot'braiz'ing-z appamtus; .the friction elements or: ibrake shoes: employedin amechanism: of; the-type just; ref-"en'scl.to are subject toweamrwhichtgraelually' increases. thetsla'ok' :orlost motion that mustfbevovercomes during. operation of the=various actuating members: of:the'assemwe; The. provision: of some: form luff automatic 'slack'take-up means? to. oompensatersuch a brake mechanism for weanisithhszdesirable. but the structural features of; the slack-r; adjster-means must necessani ly be: catching devised because of the'l'imitationsiofithe spaceizavailabie.

The principalwobgiectiof 'mytiliventibn isito provi'de amimprovedautomaticlslackraclj usterl mechanism of compact and relatively simpleconstruction'. which. may readilybe made" part of a brakapparatus ofthe: class" describedwithout imonly increasingthe .biil'kvof.thezassembly or interfering with the normal operation of the" assotion";i

Fig. 2 is; a fragmentar sectional view of the same typeof brakeapparatus'emhodying a dif- Figs. 3 and 4 are enlarged detail sectionalviews taken respectively along the lines 3-3 and 4-4"0fFig. 2;

Fig. 5 is afrag'mentary sectional view of a similar .brake apparatushaving associated therewith a...s1'ac'ke1= adjuster embodying stillanother.form of the invention; and.

section,

suitable construction, not illustratedinthe. drawings. Since thebizakerequipment, assuch, is-be 10nd. the scope. of the.presentinvention, (only .suclmelements of. the. drive. shaft. brakingapparatus as arenecssary for disclbsunepimy .improved-slack. adjuster.mechanism. are shown. in Big. .1. 'Ilhis braking. apparatus. includesa.casing structure- L2. which. is. suitably mountedon. the

vehicle .in association. withtheitotarrydrive. shaft l-.0;..andWhiChPGIICIOSGS .a mtanybrake drum secured to. the drive-shaft. andbrake. shoe elements Y (not shown). cooperative therewith. in. response0 adapted tone. moved into. braking, engagement -with.;the. brake. uponclockwiserotation. of that-camshaft.- .l=-3,..and are constructed. andar- ..ranged to bewithdrawn. to, release, position. during.counterclockwise.rotationlof. a shaft.

The brake apparatusliurther comprises means .f-or operating. thecamshaft 13- .including an ar- 1 cnate lever; it t5..hav.ing. one. end:rotatablymounted .on theicam .shaft...and thenother or free enddisposed..at-the..side of the .driyeshafi. llll opposite thevcam shaft.Fox-actuating thelever I.5..,t.o. ef-.

' fectapplication oi the. brakes. there .is. provided .aheavy:coilspring. i], .onaend of. whichis mounted in.-a spring..guideelement. 1.8..seeured. to the casing. structure and the other endoi which .45

bears. against aeolian l9. .carriedby a. plunger 20 engaging. the treeend-of the lever. The spring .IJ is operativejwhen expanding to causeoperation otthe lever in .a clockwise.direction with re-, spect to thecam shaft I.3,,. as shown in Fig, 1. It will .be noted. that. theseveral elements just 7 describeii includingthe brake application spring[1, the lever I5 and the'cam shaft l3, are all disposed within a. casingstructure 22, which ispreferahly supported by the main casing structure55. I2 through the medium of rubber shock absorb rotary member 36.

48 is a relatively flat surface which is env plunger 20, the plungerbeing constructed and arranged for operation by a suitable piston,

not shown, which is mounted within a cylinder 21 forming part of thecasing structure. The other elements of the hydraulic means operable tocause upward movement of the plunger 25- may include a pump 29 anddriving motor 30 therefor, which may be of any suitable constructionsuch as that disclosed in the aforementioned patent application, andneed not be It will be understood that described in detail. when it isdesired to effect a release of the brakes, the motor 36 is energized fordriving the liquid pump 29 and thereby increasing the pressure of fluidcontained in the cylinder 21, the fluid pressure being effective to movethe plunger 25 and adjacent end of the lever upwardly against the forceof the spring I According to the invention as disclosed in Fig. 1,'theend of the cam shaft I3 outwardly of the portion on which the lever I5is journaled is provided with a plurality of longitudinally arrangedribs 35. A rotary member or look element 36 is mounted on this end ofthe cam shaft, and has formed therein a suitably slotted opening adaptedto receive the ribbed end of the shaft so that the two elements aresecurely locked together.

The rotary member 36 may be substantially semi-circular in form; withthe opening for receiving the cam shaft I3 disposed centrally of thearcuate surface 38 of the rotary memben Carried on an extension I5a ofthe lever I5 is a pin 46, which is disposed outwardly of the curvedsurface 38 of the rotary member and has pivotally mounted thereon a pawl4|. A spring 43 is mounted on the lever I5 for holding the pawl 4|normally in engagement with a toothed portion 42 of the curved surface38, the pawl 4| being so positioned with respect to the teeth formed onthe rotary member as to transmit braking force thereto when the springI1 is rendered effective to apply the brakes, as hereinafter explained.The pawl 4| is on the other hand yieldable to permit release movement ofthe lever I5 relative to'the rotary member 36 when the latter element isheld stationary.

For measuring the angle through which the cam shaft I3 and rotary member36 are moved in effecting an application of the brakes and for limitingthe extent of release movement thereof, there is provided a rotary pawl45, which is pivotally mounted on a pin 46 carried by 2, lug 41' formedon a cover plate 48, which may be bolted or otherwise secured to theeasing structure 22. The pawl 45 has a plurality of teethdisposedconcentrically of the pin 45 and engageable with similar teeth49'formed on an extension of the curved surface 38 of the Formedadjacent the teeth gageable with the curved surface 38 of themtarymember 36 when the pawl 45 is turned in a clockwise direction duringrelease movement of the rotary member 36 and other elements of the brakeequipment. As will hereinafter be explained, the various elements areillustrated in a brake application position, wherein counterclockwisemovement of the pawl 45 is resociated control apparatus, not disclosedin the present specification. With the spring I'| thus.

rendered operative to exert braking force against the free end of thelever I5,that elementis caused to transmit corresponding torque throughthe medium of the pawl 4| to the rotary member 36 and cam shaft I3,thereby effecting application of the brakes contained within the housingI2. When it is desired to effect the release of the brakes, the motor 30is energized to drive the pump 29, and the resultant increase in fluidpressure acting on the piston associated with the piston rod 25 causesit to move the lever I5 in opposition to the force of the spring H, thelever being thereby turned in a counterclockwise direction with respectto the axis of the cam shaft l3. 'It will be understood that suitablerelease springs are associated with the brake shoe mechanism housedwithin the casing l2, so that as the brake applying force is withdrawnfrom the cam shaft I3 as just explained, these springs in effectingrelease movement of the associated brake shoe elements also causecounterclockwise rotation of the cam shaft and the attached rotarymember 36, the release movement of these elements and of the lever I5being simultaneous. As the rotary member 36 is thus lease movement ofthe rotary member 36 and the associated elements is completed, the pawl45 should be so positioned that the surface 5| thereof will lie closelyadjacent or bear slightly against the curved surface 38 of the rotarymember.

After wear of the brake shoes and other elements contained in thehousing |2 has increased the distance through which such elements mustbe moved in effecting application Of braking force to the drive shaftI0, subsequent operation of the spring I1 in effecting an application ofthe brakes will carry the lever I5, pawl 4I, rotary member 36 and camshaft I3 in'a clockwise direction to a braking position beyond thatnormally assumed by the elements. I When the rotary member 36 is thusturned beyond the normal angle for producing an application of thebrakes, the rotary pawl 45 is forced in a counterclockwise directionbeyond the position in which it is shown in Fig. 1', until one of theteeth 49 of the rotary member has been carried over the last in line ofthe teeth 48 formed on the pawl. The spring 53 meanwhile continues tourge the pawl 45 in a clockwise direction, so that after displacement ofthe rotary member 36 with respect to the pawl, the teeth 48 willnevertheless remain in meshing relation with the teeth 49.

During the next release operation of the brake mechanism, upwardmovementof the fluid pressure actuated piston rod 25 against theopposing ascent:

Ioree of the spring: 11' causesthe'usuall' turning of thelever ilfl iinacounterelockwise direction with respect "to the axis of the cam shaftr3, which is rotated .in the same directiomwhilethe brake elementswithin "the housing 1! are moved to? release position ashereinberoreexplained. Since the teeth "49*"have been displaced respectto the'teeth'ldofithe rotarypawl Hi however, movement of the pawl #5' maclockwise directionihto itslo'cked position wherein the surrotary member36 will occur beforethe lever t5 has been moved to'its' "lullreleaseflposition by peration pftfhe piston rod 25 and associatedelementsz .(Lonsequentiy; the rotary member-3B and cam shaft 13 arelocked against further movemerit. whichzthe lever 15' continues:movingt'oward its usual release: position'. During such movement of thelever 15" relaftive1t0 the locked rotary ,menibier 3B the pawl. '4?!slides over" one" .or'more off theteeth d'l', so thatthetn'ewjpositionof'th'e lever 15 with respect. to the rotaryymember 3'6 willloemaintaine'dgduring, the following applicaa tionto'fthe'brake v n It.w'ill'be apparent that the" looking or thelever 15in thenew positionwith respectto'th'ej rotary member '36 and brake camsliaftftitwillbeeffective to compensate for any slack or lost motion previouslydeveloped, so that the desiredieffic'iency and uniformity of operatingchaLracterist'ics of" the brake mechanism; with respect to otherunit'sassociatedltherewitm are thusautomatically maintained;

a Embodiment in Fig. 2"

Illustrated in Fig. '2 of thedraw-ingsis a brake "W, eadhhf'whichhasoneend secured toa pin 1*5 upon which the roll-er is journ'aled, and"its 7 mechanism similar to that -shown in Fig. *1 but embodying slack'adiuster means consfiructed'qin accordance the-invention. i

The general c'haracteristics ofthe "brahe'mechanism shown in "Fig. 2winhe understood rrom with a somewhat different for-m of "thedescription already presented conn'ectit-mi with Fig. I, it -heiirrgknown thatsuitahle "bra k'e shoeelements; not shown, areprovicled forapplying Braking force tb the have shaft lfl inaccordance with"operation of a rotary cam shaft 13a through the mediuni'ofanan' arcuatelever 65 which is movable toward brake-azppl i ca tion-po- 'sitionf'hyspringlLcr toward praherelease posi- 'tionhyflthe usual fluid pressurerelease means including the piston rod 251 The brake mechanismincludingthe slack adjustermeans shown. in Fig; 2 is contained withinacasin gstructure GU-which is supported through the mediu rrr-of theruhber'mountin'g elements-23 and 24% as may "be seen in Figs; 3 a-nid' lthecani shaft F3 11 is provided with a "plurality of lon itudinal ribsseam terminates in a reducedf'pertion 6 1.7

The ended? the lever '65 associat-ed with the can; shaft isbi-furcatedto forma pairof spaced' portions- 85 that'are'adapted tostraddie a semi-circu'lar rotary memher'fil; which is adapted to servelever 65- are provided with" suitable bores conforming to the cam shaft1 3a; and the reduced portion 61? thereof, on the rev ews- 011a*naledi'whiie" the rotary member 6 1 has'a grooved aperture fittingthecanr' shaft T-ibs SW, and is'thus" adapted to be seurerhagainstrotationreiative to'thecam shaft. As hest' shown in 2; thesemi'eirciilarlrotairy" member' im' has formediirreonaourvedhearingsunraeecnwmen roller.

isdisposedconoentrica lly oi the axis: of tihe cam "shaft-Win i "Thespaced portions#6?of the azrcuatevlevernfi arejbined by a transverse endportion 159 which may e' fitted with a bearing-'elemerrt mgas shown inFigs; Wand-4; Inter-posed between the bearing element 1 0 and the curvedsurface 89 0f the member 6'! is a lock roller 12, which is yield'ingl'ywedged inf "interlocking relation with the two elements by the f'orce of-a pair of" tension springs other end secured to onepf a pair =of'lugs'IG carried on" the s paeedportions fili. As isbe'st show-n in'fFi'g; 2ithe-hearihg element was cantedwith respect to the surface 69 of"-therotary member 61, and isrsnspaced therefrom as to prevent the roller'12" frombeing pulled downwardly beyond a normal posi-tion, asillustrated in Fig; 2; under the-force or the spring 1W, al'tl'muglr'i=theroll'er is free for movement in'the' opposite direction against theforceofthe spring. TherollerT-zthus adjacent portion 6'6" of the roller65; as shown in Fig. 3. The lock roller"80"is disposed{ in rollingengagementwi'th a bearing surface 81 for-med in a plug element 88;wh'ieh -is' firmly an chored in a suitable depression formed in anenlarged portion 89'- of'the-casing' wall; The bearing surface *S'I' ofthe plug element "is canted with respect tothe adjacent portion of thecurved surface .69 of the rotary elementidllthe two :surfiacesslbeing sosp'aced apart as "to preventuthe" roller'flfliirom being moveddownwardly beyond a nonmalt-or locking position a-s'i'llu'strated,although thesroller is freerto move'upwardlytoward' a stop member 191i;whichis= adiusta'bly mounted'inasuitable?lug extenlding from the casing:portion 85.; To "prer vent the roller E0 iromf sliding" on" the" surface81, a pair or -pins M-zaretinsertedwin ther'iplugc elemerit 1&8 and are:adaptedz to extend into suitable apertures-formed in theadj-acentportio'n of the .InvFigi. i2 0f' the-drawings, the" variousoperating elements! of: thebrake mechanism are illustrated in a brakeapplying position. The:e1ements-=are moved to this position in the usualmanner upon release of fluid under pressure from the cylinder 21 toallow expansion of thebrake application spring, f1, ashereinbeforeexplaind lso that the spring is renderedoperative to move the lever 651downwardly or in a clockwise direction with respect to the axis of theshaft l"3a. Through "the medium of thejock roller'lZ the lever 65 thusforces the rotarymember; 61' and the connected cam shaft I'Bai in a.clockwise direction to effect a plication of the brakes;

When thetrotary member GT is thus operated to turn the cam shaft l3a"in" a" clockwise direc-' 'tion in efiecting an application of thebrakes,

the lock roller 80 engaging. the curved surface 69-01 the rotaryniem'ber is rolled upwardly towardthe stop element 90.; which is; setjina predetermined position for limiting such movement of the lockroller-at a point corresponding with application of the associated brakeshoes, not shown, with maximum braking force, and with maximum allowableslack movement or lost motion. As already pointed out, the elements ofthe brake mechanism shown in Fig. 2 are positioned in braking position,it being observed that the lock roller 80 is held substantially inengagement with the stop element 90.

To effect a release of the brakes, hydraulic force is applied in theusual manner through the medium 'of the piston rod 25 to overcome thepressure of spring I! and to raise the lever 65, which is thereby turnedin a counterclockwise direction with respect to the axis of the camshaft I311. The usual release'springs associated with the brake shoesare then permitted to shift those elements, together with the cam shaftI3a and rotary member 61, toward release position, while the lock roller80 is at-the same time rolled away from the stop element 90. It will beunderstood that under normal conditions when slack movement of the brakeelements has not been excessive, both the brake lever 65 and the rotarymember 61 are brought to their full release positions at substantiallythe same time and before the roller 80 has traveled far enough to becometightly wedged between the bearing surface 81 and the curved surface 69.

If excessive slack subsequently develops in the brake assembly, so thatin effecting an application of the brakes the lever 65, rotary member61, and cam shaft I 3a are forced clockwise beyond the normal brakingposition in which they are illustrated in Fig. 2, the lock roller 80 isthen stopped upon engagement with the stop element 90, while the curvedsurface 69 of the still moving rotary member is slipped under the rolleruntil the desired braking force is brought to bear against the shaft I.It will readily be apparent that the amount of relative displacement ofthe rotary member 51 with respect to the roller 80 is a measure of theslack existing within the brake assembly.

By reason of the new position of the roller 80 on the surface 69 of therotary member, when the various elements of the braking assembly arecaused to move toward release position, the counterclockwise rotation ofthe rotary member 61 will effect wedging of the lock roller 80 betweenthe surfaces Bland 69, as hereinbefore explained, prior to completemovement of the lever 65 to the normal full release position.

With the rotary member 6'! thus locked against further counterclockwiserotation, the lever 65 and lock roller 12 are then shifted with respectto the rotary member 61, thereby compensating for the slack.

Embodiment shown in Fig. 5

Referring to Fig. 5 of the drawings, the braking assembly thereindisclosed includes an arouate brake lever 95, which like the brakelevers I5 and 65 hereinbefore described is arranged to control operationof a cam shaft associated with the usual brake shoes, not shown, the camshaft being in this case designated at l3b. The end of the brake lever95 opposite that journaled on the cam shaft is interposed between theplunger 20 controlled by the brake application spring I1, and the pistonrodv 25 associated with the hydraulic cylinder 21.

.- Secured to a ribbed portion of the cam shaft I3b is a rotary memberor disk 91, which, as shown in Figs. 6 and 7, is interposed betweenspaced legs 98 of the bifurcated end of the lever 95, which legs aresuitably apertured for receiv- The friction ring element I00 comprisesan 7 annular contractile portion surrounding and releasably gripping thedisk 91 and terminating in an enlarged lug portion I04 which partiallyoverlaps the end of the contractile portion, as shown in Fig. 5. The lugportion I04 is interposed between a stationary stop lug I05 and anadjustable stop bolt I06 carried by the casing structure of the brakeassembly. The lock ring element I00 is so disposed on the rotary disk 91as to check counterclockwise rotation thereof after the lug portion I04has been brought into engagement with the stop lug I05, due to thebinding effect of the contractile portion on the peripheral surface ofthe disk. The friction ring element I00 is on the other hand adapted torelease its grip on the rotary disk 91 upon clockwise movement thereofcausing engagement of the lug portion I04 with the stop bolt I06, asdisclosed in Fig. 5. 1

The other friction ring element MI is similar to that just described,and includes a contractile portion fitted about and releasably grippingthe peripheral surface of the rotary disk. 91, and a lug portion I08,which partially overlaps the free end of the contractile portion whichend is diametrically opposite 'the free end of ring element I00. The lugI08 is pivotally connected by means of a pivot pin 1 09 to the brakelever 95 through the medium of a bifurcated link IIO, the forked end ofwhich is journaled on the pin I09 and the opposite end of which isjournaled on a pin I I I carried by the lever 95. It will thus be seenthat the friction ring element IOI is con structed and arranged forcontraction to grasp the rotary disk 9'! upon clockwise movement of thelever 95 in effecting an application of the brakes, but is adapted tobecome expanded and to slip over the disk when the lever 95 is movedtoward release position.

In principle, the operation of the slack adjuster elements of the brakeassembly shown in Fig. 5 is similar to the operation of the mechanismshown in Fig. 2. When it is desired to effect an application of thebrakes, the associated brake control means is operated in the usualmanner. to withdraw hydraulic pressure normally transmitted by way ofthe piston stem 25 to the brake lever 95, so that the brake spring I1 isrendered effective to force the adjacent end of the lever downwardly, asviewed in Fig. 5. In so moving, the lever 95 exerts a pulling forcethrough the medium of the link H0 and pin I09 on the lug portion I08 ofthe friction ring element IOI, which is thereby tightened into grippingrelation with the rotary disk 9'! for turning the latter and theconnected cam shaftv I31) 'by the casing structure, at approximately themoment the other elements including the brake lever 95 are stoppedinfull release position.

When an application of the brakes is effected after the development ofslack or lost motion in mally rotatable through a certain angle foreffecting application and release of the brakes and an actuating lever'cooperable with said cam shaft, in combination, a disk member securedconcentrically on said cam shaft, a pair of contractile locking ringelements fitted on said disk member, means operatively connecting one ofthe brake assembly, however, after movement of I the lug portion I04 ofthe friction ring element I00 into engagement with the stop bolt I06, asshown in Fig. 5, the further rotation of the rotary disk 91 and camshaft I3b necessary to effeet application of the, desired braking forceresults in a corresponding change in the relative position of thefriction ring element I00 on the disk, since the friction ring is atsuch times caused to relax .its grip on the disk as hereinbeforeexplained. During the subsequent release operation, the lug portion I04of the friction. ring element I00 is carried into operative engagementwith the lug portion I05 provided on the casing structure, beforecompletion of move ment of the lever 05 to full release position. Thefriction ring element I00 is thus rendered operative to check furthercounterclockwise movement of the rotary disk 91 and brake cam shaft I3b,while the brake lever 05 continues its release movement, acting throughthe medium of the link H0 and lug portion I08 to cause the otherfriction ring element IOI to slip into a new position with respect tothe rotary disk.

Each of the three different forms of the invention, as embodied in thebrake equipments disclosed in the foregoing description, is thusconstructed and arranged to effect automatic takeup of lost motionbefore slack movement develops sufliciently to impair the efiiciency ofthe brakes, and although of sturdy construction, is designed to fitwithin the small spaceavailable in a brake assembly of the springapplied, fluid released type illustrated.

Having now described my invention, what I claim as new and desiretosecure by Letters Patent, is:

1; A slack adjuster mechanism for a brake assembly of the type includinga cam shaft norsaid locking ring elements to said lever for transmittingbrake application force from said lever to said disk member, and meanscooperative with the otherlocking ring element, following undesiredrotation of said cam shaft beyond said certain angle in effecting anapplication of the brakes, for checking release rotation of said disk,member and cam shaft at a predetermined point before said actuatinglever has reached its release position. i

2. In a slack adjuster mechanism for a brake device having a camshaftnormally rotatable through a certain angle in effecting applicationand release of the brake, and a lever pivotally connected to said camshaft and constructed and arranged to actuate same, the combination of arotary disk member secured to said shaft adjacent said lever and adaptedfor rotation with said shaft; a contractile clutch element mounted onsaid disk member, means connecting said clutch element to said leverwhereby brake apher for turning said shaft with the lever, a contractilelocking element having a projecting lug portion and adapted to be flexedinto gripping relation with said disk member in a reverse direction withrespect to said clutch element, a stationary stop member disposed forcooperation with said lug portion of the locking element for limitingrotation of the cam shaft during movement of said lever in releasing thebrake, and an adjustable stop member cooperative with said lug portionfor causing said locking element to expand and slip on said disk member,in the event of excessive rotation of said cam shaft beyond said certainangle in applying the brake, whereby upon subsequent return movement ofsaid cam shaft to release the brake said associated elements will havebeen automatically ad- CECIL S. IGILLEY.

